In a lean-burn engine equipped with a turbocharger, a responsiveness of a super-charging pressure in a lean region is enhanced by control of a valve timing of an exhaust valve while a combustion state is restrained from varying. A variable valve mechanism that can change an opening timing of the exhaust valve while keeping a closing timing of the exhaust valve constant, is included in the lean-burn engine. When a target operation point is located in the lean region, and when an actual supercharging pressure is lower than a target supercharging pressure, supercharging pressure increasing control that advances the opening timing while keeping the closing timing constant is executed by operating the variable valve mechanism.

In a lean-burn engine equipped with a turbocharger, a responsiveness of a super-charging pressure in a lean region is enhanced by control of a valve timing of an exhaust valve while a combustion state is restrained from varying. A variable valve mechanism that can change an opening timing of the exhaust valve while keeping a closing timing of the exhaust valve constant, is included in the lean-burn engine. When a target operation point is located in the lean region, and when an actual supercharging pressure is lower than a target supercharging pressure, supercharging pressure increasing control that advances the opening timing while keeping the closing timing constant is executed by operating the variable valve mechanism.

An engine control system with a variable turbocharger may include an engine including a cylinder generating power by combustion of a fuel, a variable turbocharger including a turbine rotated by exhaust gas exhausted by the engine, and a compressor rotated in synchronization with the turbine and compressing external air and supplying the compressed air to the cylinder, a vane adjusting flow area of exhaust gas supplied to the turbine, and a controller dividing an operation region of a vehicle into a steady-speed driving region, an acceleration driving region, and a deceleration driving region from a fuel amount supplied to the cylinder and a required torque of the engine, and controlling opening of the vane and an injection timing of fuel injected into the cylinder.

Methods and systems are provided for controlling boost pressure in a staged engine system comprising a turbocharger and an upstream electric supercharger based on altitude. During vehicle operation at higher altitudes, where vacuum availability for wastegate actuation is limited, boost pressure may be provided by operating the electric supercharger more aggressively. The wastegate may be used for boost control once the vacuum reserve is replenished.

Methods and systems are provided for controlling boost pressure in a staged engine system comprising a turbocharger and an upstream electric supercharger. In one example, a method may include coordinating the operation of the electric supercharger and an electric supercharger bypass valve and to open the electric supercharger bypass valve to reduce the extent and duration of electric supercharger overboost.

A system and method for compensation of turbo lag in hybrid vehicles is disclosed. The system identifies a zero boost power limit of the engine and a torque curve power limit. A turbocharger dynamic model is then developed based on measurements of the input engine power and the output max available engine power. The model is used to determine an overall propulsion power limit based on the combination of the engine and motor in operation. A power request by the driver may then be limited to the overall propulsion power limit to compensate for the effect of the turbocharger when propelling the vehicle using both the engine and motor and better simulate the engine-only response.

A system and method for compensation of turbo lag in hybrid vehicles is disclosed. The system identifies a zero boost power limit of the engine and a torque curve power limit. A turbocharger dynamic model is then developed based on measurements of the input engine power and the output max available engine power. The model is used to determine an overall propulsion power limit based on the combination of the engine and motor in operation. A power request by the driver may then be limited to the overall propulsion power limit to compensate for the effect of the turbocharger when propelling the vehicle using both the engine and motor and better simulate the engine-only response.

A device for measuring temperature of a turbine wheel in a turbocharger includes: a guide that passes infrared ray generated from the turbine wheel and includes a coolant path; a protection unit that protects an optical head which senses the infrared ray; and a signal processing unit that measures a temperature of the turbine wheel by processing a signal corresponding to the sensed infrared ray.

A control system for a work vehicle includes an acceleration detection device and a controller. The acceleration detection device detects an acceleration of the work vehicle. The controller determines whether the acceleration is greater than a first threshold and reduces the a vehicle speed when the acceleration continues to be equal to or greater than the first threshold over a predetermined first determination time period.

In a hybrid vehicle, in a case where a temperature of a catalyst is equal to or larger than a prescribed temperature that is a temperature at which purification of an exhaust gas in the catalyst begins, and charging of a storage battery is not restricted, at least one of an engine load, an engine speed, and a retard angle amount of an ignition timing is made to gradually increase, and in a case where the temperature of the catalyst is equal to or larger than the prescribed temperature and the charging of the storage battery is restricted, the engine load is fixed and at least one of the engine speed and the retard angle amount of the ignition timing is made to gradually increase.